The 30-year-old quarterback, who opted out of his contract with the San Francisco 49ers in 2017 and remains unaffiliated to any NFL team, tweeted a black-and-white photo of himself featuring the Nike logo and “Just Do It” slogan as well as a quote: “Believe in something. Even if it means sacrificing everything.”
Nike retweeted Kaepernick's post, but representatives for Kaepernick and the NFL have not yet commented.
"We believe Colin is one of the most inspirational athletes of this generation, who has leveraged the power of sport to help move the world forward," said Gino Fisanotti, a Nike vice president of brand for North America, according to ESPN.
Nike has endorsed Kaepernick since 2011 but has not featured him in campaigns since his departure from the NFL.
The decision to feature Kaepernick so prominently in the advertising campaign for the 30th anniversary of Nike's “Just Do It” motto is likely to prompt a reaction from some NFL fans, as well as President Donald Trump, who has said he would love to see NFL owners fire football players who disrespected the American flag.
— Colin Kaepernick (@Kaepernick7) September 3, 2018
News of Nike's ad campaign broke just days before the first game of the NFL season on Thursday, when the controversy over pre-game protests could flare anew.
This season, the NFL has adopted a rule requiring all players to stand during the anthem, although it gave them the option of staying off the field until the ceremony was over. Even so, the protests have persisted through the preseason and the NFL has said it is in discussions with the players union on the policy.
In 2016, Kaepernick became the first NFL player to take a knee in protest of growing racial disharmony across the United States, including police shootings and instances of police brutality
"I am not going to stand up to show pride in a flag for a country that oppresses black people, and people of colour," Kaepernick said in a press conference after first sitting out during the anthem. "To me, this is bigger than football, and it would be selfish on my part to look the other way. There are bodies in the street, and people getting paid leave, and getting away with murder."
Mr Trump's anger towards the protesting players prompted more to join, in-turn morphing the demonstration into something of direct resistance to his administration's handling of race issues.
Additional reporting by agencies